The present invention relates to connectors for electrical conductors in general, and more particularly to improvements in connectors of the type wherein one or more wire-like or analogous electrical conductors can be clamped between a biasing device and the internal surface of a wall forming part of a shackle. More particularly, the invention relates to improvements in connectors of the type wherein the wall of the shackle defines an internal socket which centers the inserted conductor or conductors and wherein the biasing device has a section which is generally complementary to the wall of the shackle and is receivable in the shackle and adapted to be moved toward the wall so that the conductor or conductors are clamped between the biasing device and the internal surface of the wall.
It is already known to employ a shackle and a biasing device in order to clamp one or more wire-like conductors to the surface surrounding the socket in the wall of the shackle. As a rule, the means for urging the biasing device toward the internal surface of the aforementioned wall comprises a screw which meshes with the shackle and whose tip can urge the biasing device toward the internal surface of the wall. Reference may be had to German Pat. No. 923 562 which discloses a series of clamps each of which can be said to constitute a connector. The patented connector is designed to reliably clamp individual wire-like conductors whose diameter can vary within a certain range. However, such connector is incapable of ensuring adequate clamping of a multiple-wire conductor, of several discrete wire-like conductors (especially if the diameters of the conductors are different) and/or of conductors having small or extremely small diameters. This is due to the fact that, if the patented connector receives several wire-like conductors, the distribution of such conductors along the internal surface of the centering wall is unpredictable with the result that the clamping action varies from wire to wire and that certain wires are likely to remain out of contact with the shackle and/or with the biasing device. The situation is analogous in the connector which is disclosed in German Utility Model No. 16 01 608. The connector of the Utility Model is particularly unreliable if the wire-like conductors are thin or very thin because the biasing device is likely to engage and bear against the centering wall of the shackle prior to clamping of such thin conductors.
German Pat. No. 11 16 294 discloses a connector which is designed to clamp discrete (single-wire) conductors, conductors which consist of several components, or several discrete conductors. To this end, the central portion of the shackle comprises inclined internally disposed beads which can extend into complementary sockets or recesses provided therefor in the biasing device. It has been found that even such connectors are insufficiently reliable if the nominal diameters of the conductors are outside of a relatively narrow range. If the diameter of a conductor is rather pronounced, the clamping action is furnished only by the ridges of the beads, i.e., the area of clamping engagement with the conductors is relatively small and the wires are subjected to the action of very pronounced buckling and shearing forces. In order to avoid such drawbacks, at least when the nonimal diameters of the conductors are within the prescribed range, the beaded portion of the shackle must be configurated in such a way that the neighboring beads are separated from one another by portions having flat surfaces. This, in turn, greatly reduces the reliability of the clamping action if the diameters of the conductors are small or very small because the clamping action of the patented connector upon thin wires is not superior to that of a connector wherein the wire is simply held between two flat surfaces. In other words, the centering action upon one or more thin conductor wires is practically nil and, therefore, such wires are likely to become separated from the connector during laying when the wires must be subjected to repeated and often quite pronounced tensional and like stresses. The exertion of a pull upon the inserted wire or wires is likely to result in removal of shavings of copper or whatever material the conductor is made of, and the unavoidable result is a loosening of connection between the wire or wires and the connector. The connector of German Pat. No. 11 16 294 is highly unreliable when the patented device is to receive and clamp several conductors having different diameters.